The US President held a press conference with Middle East ally King Abdullah of Jordan

It came after US ambassador Nikki Haley threatened strikes as fury mounted over the sickening nerve gas attack which Trump branded an “affront to humanity”.

“The president himself is making calls to senior members of Congress saying he is seriously considering something he said he would never do, not that long ago, which is military action in Syria,” CNN reported.

Trump is reportedly discussing his strategy with Defense Secretary James Mattis.

Rex Tillerson, left, said plans were being formed to remove Assad from power

One Trump administration official told DailyMail.com the president wanted to send a message to Assad and Russia that he’s “deadly serious”.

The claims came as Rex Tillerson, the US secretary of State, announced that “steps are underway” to bring together an international coalition to remove Syrian President Bashar al-Assad from office following the horrifying chemical attacks.

Speaking at a press conference, Tillerson said: “Assad’s role in the future is uncertain, clearly, and with the acts that he has taken, it would seem that there would be no role for him to govern the Syrian people.”

When quizzed on what steps the United States would be prepared to take, he replied: “The process by which Assad would leave is something that I think requires an international community effort—both to first defeat ISIS within Syria, to stabilize the Syrian country, to avoid further civil war, and then to work collectively with our partners around the world through a political process that would lead to Assad leaving.”

When asked about plans to organise an international coalition, Tillerson said: “Those steps are under way…It’s a serious matter. It requires a serious response.”

Bodies fill a truck after 100 people were reported to have been killed in the gas attack

“The UK has led international efforts to call to account the Syrian regime and Daesh for the use of chemical weapons and I would urge the Organisation for the Prohibition of Chemical Weapons to investigate this incident as soon as possible.

“I’m very clear that there can be no future for Assad in a stable Syria which is representative of all the Syrian people and I call on all the third parties involved to ensure that we have a transition away from Assad.

Mohammed Hassoun, a media activist documenting the attack for the medical society, said medics had told him there was likely more than one chemical used.

He said: “There are 18 critical cases here. They were unconscious, they had seizures and when oxygen was administered, they bled from the nose and mouth… chlorine gas doesn’t cause such convulsions.”

Survivors of the attack received no mercy as a rocket slammed into a hospital filled with the victims, raining rubble down on top of medics battling to save people.

The National Coalition has now called on the UN Security Council to “convene an emergency session…, open an immediate investigation and take the necessary measures to ensure the officials, perpetrators and supporters are held accountable”.

The statement added: “Failure to do so will be understood as a message of blessing to the regime for its actions.”

It accused the “regime of the criminal Bashar” of carrying out the attack, using “shells containing chemical gas”.

DEADLY CHEMICAL WEAPON: What are the effects of nerve agent sarin?

Doctors treating some of the victims in the suspected chemical attack in Syria said they had symptoms matching those caused by exposure to sarin.

Sarin is a deadly nerve agent used in chemical warfare.

It was banned by the chemical weapons convention. Sarin has similar harmful effects to certain kinds of insecticides (insect killers).

Some of the symptoms of sarin poisoning include: Difficulty breathing, foaming at the mouth, convulsions and paralysis.

Foreign Secretary Boris Johnson has condemned the attack and said Assad will be guilty of “war crimes” if he is behind it.

The Syrian army could not immediately be reached for comment. Damascus has repeatedly denied using chemical weapons.

A Syrian military source said last week allegations that government forces were using chemical weapons were “devoid of truth”.

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